The counterfeit drug business originated with lifestyle drugs, such as the erectile dysfunction drug. Now, however, counterfeits in almost any therapeutic category may be purchased by Americans through internet pharmacies. In fact, the Pharmaceutical Safety Institute found in 2010 that counterfeits in the metabolic disease category grew fastest (2), with the troubling implication of a shift by counterfeiters to life savig medicines. Linking on-dose authentication of package contents to packing security is a global unmet need in pharmaceutical anticounterfeiting: Product authentication is the means whereby a legitimate product may be distinguished from a counterfeited fake designed to resemble the genuine article, and from gray market or stolen legitimately manufactured products. Because of the ease with which particular pharmaceutical dosage forms can be repackaged, relabeled, or sold unpackaged, package level security is insufficient to assure authentication of package contents. Recently FDA issued new guidance (14) for incorporating physical chemical identifiers (PCIDs) (12)(13), usually in the form of labeled polymeric microparticles, to assist in product authentication. These microparticles may be prepared from generally regarded as safe (GRAS) host materials and FDA approved dyes to be used as PCIDs. Our hypothesis is that a simple and reliable on- dose authentication may be achieved via a relatively small number of PCIDs prepared with different physical characteristics if these are applied to doses combinatorially to create a large number of statistical patterns that can be recognized by simple instrumentation. CertiRx has unique, patented and patent-pending methods for incorporating an FDA Guidance-complaint signature on to solid oral dosage form (SODF) product's surface, using specially designed sets of PCIDs. We expect that further developing the CertiRx methods will make it easier to detect a counterfeit drug and deter legitimate product theft and diversion. To test our hypothesis the following specific aims will be addressed: (1) PCIDs will be deposited on model SODF selected on the basis of their importance as highly counterfeited drug products; (2) Imaging technology will be employed to evaluate the effectiveness of labeling as a means to establish authenticity. PUBLIC HEALTH RELEVANCE: The counterfeit drug business originated with lifestyle drugs, such as the erectile dysfunction drug Viagra, but now however, counterfeits in almost every therapeutic category including life-saving medicines (2). Linking on-dose authentication of package contents to packing security is a global unmet need in making counterfeits pharmaceuticals easier to detect and deterring diversion of legitimately manufactured pharmaceuticals. Our hypothesis is that a simple and reliable on-dose authentication may be achieved via a relatively small number of PCIDs prepared with different physical characteristics if these are applied to doses combinatorially to create a large number of statistical patterns that can be recognized by simple instrumentation.